TWI525136B - Resin film - Google Patents

Description

Resin film

The present invention relates to a resin film which is suitable for use as a sacrificial layer when manufacturing a microstructure having a hollow structure in the field of MEMS (Micro Electro Mechanical System) technology.

A MEMS technology in which a fine structure is formed on a semiconductor substrate such as a germanium or an insulating substrate such as glass or on a metal is currently under development.

Among the fields of MEMS technology, a sacrificial layer can generally be used in the manufacture of a microstructure having a hollow structure. For example, by forming a sacrificial layer between the upper and lower electrode layers and then selectively removing the sacrificial layer, it is possible to form two electrode structures arranged to be spaced apart from each other (see Patent Documents 1 and 2).

From the viewpoint of film formation at a low temperature and easy patterning, etc., the sacrificial layer used for such a purpose may be an organic resin. For example, Patent Document 1 describes an organic resin using a polyimide resin, a BCB resin, a fluororesin, or a polyamide resin.

In Patent Document 1, a sacrificial layer is formed by a coating method, and a sacrificial layer having a uniform thickness is easily formed, and a number of steps is reduced when a sacrificial layer is formed, and the like is employed, and a portion for forming a sacrificial layer is used. It is advantageous to form a sacrificial layer from a subsequent resin film.

Further, Patent Documents 1 and 2 also describe ashing methods such as ashing by oxygen plasma or by heating the sacrificial layer while being exposed to odor. Ashing in an oxygen environment. However, in these methods, it is necessary to remove the residue after ashing.

In this regard, if the sacrificial layer can be dissolved and removed by a solvent or the like, it does not occur after the sacrificial layer is removed, and is suitable.

As the adhesive film for a semiconductor, it can be used as a sacrificial layer for the above use.

For example, the articles described in Patent Documents 3 and 4 are known as a film for a semiconductor.

However, in the adhesive film for a semiconductor described in Patent Documents 3 and 4, since the acrylic copolymer contained in the component has a low glass transition point (Tg), it is likely to stick at a normal temperature of 30 ° C or lower. Therefore, when the film is placed on a portion where the film and the sacrificial layer are formed, it is difficult to remove the bubbles existing between the two. When the air bubbles are left in a state in which the air bubbles remain between the two, the air bubbles are expanded during the thermocompression bonding, and there is a concern that peeling of the sacrificial layer or positional displacement occurs.

Further, in order to prevent foreign matter from adhering to the adhesive surface, the adhesive film before use is stored in a state of being sandwiched by a protective film such as a polyethylene terephthalate (PET) film, but if the film is adhered to the film, It becomes difficult to separate the adhesive film from the protective film.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2011-83881

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-214480

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2002-180021

[Patent Document 4] Japanese Laid-Open Patent Publication No. 2006-182919

The present invention has been made to solve the above problems in the prior art, and an object thereof is to provide a resin film which is suitable for use as a sacrificial layer used in the field of MEMS technology.

The properties required for this resin film are as follows.

‧It will not stick at room temperature below 30 °C.

‧ Excellent adhesion when thermocompression bonding by rolling.

‧ When the thermocompression bonding is performed by calendering, the dimensional change is small.

‧ Excellent processability when patterning by laser.

‧ Excellent plating resistance.

‧ After heat hardening and processing, the film can be removed by dissolution with an organic solvent.

In order to achieve the above object, the present invention therefore provides a resin film comprising (A) an acrylic resin having a glass transition point (Tg) of 40 to 80 ° C and having a functional group reactive with an epoxy resin, and (B) an epoxy resin. And (C) a phenol resin and (D) tetraphenylphosphonium tetra(p-tolyl) borate.

Among the resin films of the present invention, the aforementioned (A) acrylic resin system It is preferred to have a hydroxyl group as a functional group reactive with the above epoxy resin.

In the resin film of the present invention, the hydroxyl value of the (A) acrylic resin is preferably from 1 to 30 [mg/KOH].

In the resin film of the present invention, the (A) acrylic resin preferably has a carboxyl group as a functional group reactive with the epoxy resin.

In the resin film of the present invention, the carboxyl group equivalent of the (A) acrylic resin is preferably from 1,300 g/eq to 39,000 g/eq.

In the resin film of the present invention, the mass average molecular weight (Mw) of the (A) acrylic resin is preferably from 300,000 to 800,000.

In the resin film of the present invention, the epoxy resin (B) is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, biphenyl type epoxy resin, and fat. At least one of the group consisting of a family of epoxy resins is preferred.

Among the resin films of the present invention, the epoxy resin (B) is preferably a bisphenol A epoxy resin.

In the resin film of the present invention, the content of the epoxy resin (B) is preferably 5 to 50 parts by mass based on 100 parts by mass of the (A) acrylic resin.

In the resin film of the present invention, the (C) phenol resin is at least one selected from the group consisting of terpene phenol resin, bisphenol A phenol resin, bisphenol F phenol resin, and novolac phenol resin. One is better.

Among the resin films of the present invention, the (C) phenol resin is preferably a terpene phenol resin.

Among the resin films of the present invention, the content of the aforementioned (C) phenol resin It is preferably 10 to 35 parts by mass based on 100 parts by mass of the (A) acrylic resin.

The resin film of the present invention satisfies the characteristics required for the resin film used for the above sacrificial layer. It is therefore suitable for use as a sacrificial layer used in the field of MEMS technology.

The invention is described in detail below.

The resin film of the present invention is composed of the components (A) to (D) shown below.

(A) Ingredients: Acrylic resin

The acrylic resin of the component (A) is a component which contributes to flexibility and dimensional stability during thermocompression bonding by rolling in the resin film of the present invention. Further, when the resin film is produced, it contributes to compatibility with other components.

The acrylic resin of the component (A) is required to react with the epoxy resin of the component (B) when the resin film is heat-cured. Therefore, the acrylic resin of the component (A) is a substance having a functional group reactive with an epoxy resin.

In the case where tetraphenylphosphonium tetra(p-tolyl) borate is used as a hardening accelerator for an epoxy resin, the functional group reactive with the epoxy resin is from the viewpoint of good reaction with the epoxy resin. Hydroxyl groups and carboxyl groups are preferred.

Among them, in the case where tetraphenylphosphonium tetra(p-tolyl)borate is used as a curing accelerator for an epoxy resin, the hydroxyl group is preferred from the viewpoint of particularly good reaction with an epoxy resin.

When the acrylic resin of the component (A) has a hydroxyl group as a functional group reactive with an epoxy resin, the hydroxyl value of the acrylic resin is preferably from 1 to 30 [mg/KOH]. If the hydroxyl value of the acrylic resin is less than 1 = mg/KOH], the reaction with the epoxy resin does not occur, and there is a concern that sufficient adhesion cannot be obtained. On the other hand, when the valence of the hydroxy group of the acrylic resin is more than 30 [mg/KOH], the reaction with the epoxy resin proceeds excessively, and the crosslinking density becomes high, and the resin film which cannot be cured by heating in an organic solvent may be dissolved and removed. Concerns.

The hydroxyl value of the acrylic resin is preferably 5 to 20 [mg/KOH], more preferably 10 to 15 [mg/KOH].

In the case where the acrylic resin of the component (A) has a carboxyl group as a functional group reactive with an epoxy resin, the carboxyl group equivalent of the acrylic resin is preferably from 1,300 g/eq to 39,000 g/eq. If the carboxyl equivalent of the acrylic resin is more than 39,000 g/eq, the reaction with the epoxy resin does not occur, and there is a concern that sufficient adhesion cannot be obtained. On the other hand, when the carboxyl group equivalent of the acrylic resin is less than 1,300 g/eq, the reaction with the epoxy resin proceeds excessively, and the crosslinking density becomes high, and there is a concern that the resin film after heat curing cannot be dissolved and removed by the organic solvent. .

The carboxyl group equivalent of the acrylic resin is preferably 2,000 g/eq to 8,000 g/eq, more preferably 2,600 g/eq to 4,000 g/eq.

The glass transition point (Tg) of the acrylic resin of component (A) is 40~ 80 ° C.

When the Tg of the acrylic resin is 40 to 80 ° C, the temperature at which the resin film is adhered is moderately high. Therefore, at a normal temperature of 30 ° C or lower, the resin film is not placed on the portion where the sacrificial layer is formed. sticky. Therefore, when the resin film is placed on the portion where the sacrificial layer is formed, the bubbles can be easily removed even if bubbles are present between the two. Therefore, the thermal pressure bonding by rolling is performed in a state where the air bubbles remain between the two, and the concern of occurrence of peeling or positional deviation of the sacrificial layer is solved. Further, it is also easy to separate the resin film before use from the protective film.

The resin film of the present invention exhibits a tack temperature of 40 ° C or higher, preferably 40 to 80 ° C, preferably 50 to 70 ° C, more preferably 50 to 60 ° C. Therefore, the resin film exhibits a temperature at which adhesion does not become extremely high, and thus it is suitable for forming a sacrificial layer by thermocompression bonding by calendering.

Further, the temperature at which the adhesion is present in the present specification means that the temperature at the time of sticking of 0.1 N or more is exhibited in the case of measurement by the probe sticking method.

When the Tg of the acrylic resin is less than 40 ° C, the effect of increasing the temperature at which the resin film is applied to the resin film cannot be sufficiently exhibited. When the resin film is placed at a portion where the sacrificial layer is formed at a normal temperature of 30 ° C or lower, Presenting a sticky concern. Further, the dimensional change at the time of thermocompression bonding by rolling increases. On the other hand, when the Tg of the acrylic resin exceeds 80 ° C, the temperature at which the resin film is adhered becomes extremely high, and it is difficult to form a sacrificial layer by thermocompression bonding by rolling. Further, compatibility with other components is lowered, and workability at the time of producing a resin film is deteriorated. Further, the resin film is inferior in flexibility.

The Tg of the acrylic resin is preferably 45 to 60 °C.

The acrylic resin used in the component (A) has a functional group reactive with an epoxy resin and has a Tg of 40 to 80 ° C, and is not particularly limited, and contains a methyl methacrylate component and acrylic acid. The methyl methacrylate butyl acrylate copolymer of the butyl ester component is preferred. Further, in the case where these components constituting the copolymer are used alone, the desired effect cannot be exhibited. When the methyl methacrylate component is used alone, the flexibility of the film is poor, and when the butyl acrylate component is used alone, it is sticky at a normal temperature of 30 ° C or lower regardless of Tg.

Among them, a methyl methacrylate component is contained in a ratio of x/y = 8/2 to 6/4 from the viewpoint that the resin film having a controlled temperature is easily obtained and the film has excellent flexibility. A copolymer of methyl methacrylate and butyl acrylate with a butyl acrylate component (y) is preferred. When x/y>8/2, the film has a tendency to be inferior in flexibility, and if x/y is less than 6/4, it becomes difficult to control the temperature at which the film is adhered by the Tg of the acrylic resin.

Further, from the viewpoint of maintaining compatibility with other components and interlayer insulation of the film, the methyl methacrylate butyl acrylate copolymer satisfies the above range with x/y and the mass average molecular weight (Mw) is 300,000~ 800,000 is preferred.

When the Mw is less than 300,000, there is a concern that the interlayer insulation of the film cannot be maintained. On the other hand, when Mw exceeds 800,000, the compatibility with other components is lowered, and there is a concern that it is difficult to produce a film.

The mass average molecular weight (Mw) of the methyl methacrylate butyl acrylate copolymer is preferably from 400,000 to 700,000, more preferably from 450,000 to 600,000.

(B) Component: Epoxy resin

The epoxy resin of the component (B) contributes to the thermosetting property and the adhesiveness of the resin film of the present invention.

The epoxy resin used in the component (B) is not particularly limited, and various epoxy resins can be used. From the viewpoint of excellent correlation between strength and heat resistance, the epoxy resin is a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolac type epoxy resin, a biphenyl type epoxy resin, An aliphatic epoxy resin is preferred.

Further, any of the above epoxy resins may be used, or two or more kinds may be used in combination.

From the viewpoint of particularly excellent correlation between strength and enthalpy, the bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferable among the above epoxy resins, and bisphenol A type is preferable. Epoxy resin is better.

The epoxy resin used in the component (B) preferably has a mass average molecular weight (Mw) of from 100 to 5,000, from the viewpoints of reactivity, adhesion, solubility, and the like.

The mass average molecular weight (Mw) of the epoxy resin is preferably from 200 to 2,000, more preferably from 300 to 1,000.

In the resin film of the present invention, the content of the epoxy resin of the component (B) is 100 parts by mass relative to the acrylic resin of the component (A). 5 to 50 parts by mass is preferred.

When the content of the epoxy resin of the component (B) is less than 5 parts by mass, there is a concern that the strength will be insufficient. On the other hand, when the content of the epoxy resin of the component (B) exceeds 50 parts by mass, it becomes difficult to adjust the compatibility with other components or the temperature at which adhesion occurs. Further, the dimensional change at the time of thermocompression bonding by rolling increases.

The content of the epoxy resin of the component (B) is preferably 30 to 50 parts by mass, more preferably 35 to 45 parts by mass, per 100 parts by mass of the acrylic resin of the component (A).

(C) component: phenol resin

The phenol resin of the component (C) functions as a tackifier for the resin film of the present invention and a hardener for the epoxy resin of the component (B). Further, when the resin film is produced, it contributes to compatibility with other components.

The phenol resin used in the component (C) is not particularly limited, and various phenol resins can be used. The phenol resin is preferably a terpene phenol resin, a bisphenol A type phenol resin, a bisphenol F type phenol resin, or a novolac type phenol resin from the viewpoint of excellent adhesion and adhesion of the resin film.

Further, any of the above phenol resins may be used, or two or more kinds may be used in combination.

From the viewpoint of particularly excellent adhesion and adhesion of the resin film, a terpene phenol resin is preferable among the above phenol resins.

In the resin film of the present invention, the content of the phenol resin of the component (C) The amount is preferably 10 to 35 parts by mass based on 100 parts by mass of the acrylic resin of the component (A).

When the content of the phenol resin of the component (C) is less than 10 parts by mass, there is a concern that the strength will be insufficient. On the other hand, when the content of the phenol resin of the component (C) exceeds 30 parts by mass, it becomes difficult to adjust the compatibility with other components.

The content of the phenol resin of the component (C) is preferably 10 to 30 parts by mass, more preferably 15 to 25 parts by mass, per 100 parts by mass of the acrylic resin of the component (A).

(D) component: tetraphenylphosphonium tetra(p-tolyl)borate

The tetraphenylphosphonium tetra(p-tolyl)borate of the component (D) can function as a hardening accelerator for the epoxy resin of the component (B) in the adhesive film of the present invention.

When the hardening accelerator of the epoxy resin is a general imidazole, a hardening reaction occurs between the epoxy resins to form a three-dimensional crosslink, so that the crosslinking density becomes high, and the resin film after heat curing cannot be dissolved by an organic solvent. .

On the other hand, if the tetraphenylphosphonium tetra(p-tolyl)borate of the component (D) is used together with the phenol resin of the component (C), the hardening reaction between the epoxy resins of the component (B) does not proceed. Between the different components contained in the resin film, that is, between the acrylic resin of the component (A) and the epoxy resin of the component (B), the acrylic resin of the component (A) and the phenol resin of the component (C) Epoxy resin of (B) component and phenol resin of (C) component Since the hardening reaction occurs between them, the crosslinking density does not become high, and the resin film after heat curing can be dissolved and removed by an organic solvent.

In the resin film of the present invention, the tetraphenylphosphonium tetra(p-tolyl)borate content of the component (D) is 0.1 to 5 parts by mass based on 100 parts by mass of the acrylic resin of the component (A). good.

When the content of the tetraphenylphosphonium tetra(p-tolyl)borate of the component (D) is less than 0.1 part by mass, the curing reaction of the epoxy resin does not proceed, and there is a concern that the adhesion is insufficient due to insufficient curing. On the other hand, if the content of the tetraphenylphosphonium tetra(p-tolyl)borate of the component (D) exceeds 5 parts by mass, the hardening reaction of the epoxy resin proceeds too rapidly, and therefore the resin film of the present invention is used as a production. When a sacrificial layer used for a fine structure having a hollow structure is used, there is a concern that it is difficult to exhibit problems such as embedding property in the unevenness.

The tetraphenylphosphonium tetra(p-tolyl) borate content of the component (D) is preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the acrylic resin of the component (A), and is 0.1 to 2 parts by mass. For better.

The thickness of the resin film of the present invention is preferably 5 to 50 μm. When the thickness of the resin film exceeds 50 μm, the thickness is too thick, so that the flexibility of the film is lowered, and workability is deteriorated. In addition, since the bubbles are caught or the solvent remains, bubbles or the like are generated in the subsequent step, so that the produced film is likely to have bubbles remaining. In addition, it is difficult to produce a film having a uniform composition. On the other hand, if the thickness of the film is less than 5 μm, the thickness is too thin, so there is a concern that the film may be cracked at the time of the next or during the operation. In addition, it becomes easy to carry static electricity, and thus the operability is deteriorated.

The thickness of the resin film of the present invention is preferably 10 to 40 μm, more preferably 10 to 35 μm.

In the resin film of the present invention, the components (A) to (D) can be dissolved or dispersed in a solvent at a desired content ratio, and the obtained solution is applied to a substrate, and then the substrate is heated to solvent. It is removed and then removed from the substrate.

The solvent to be used at this time may, for example, be methyl ethyl ketone having a low boiling point, acetone, methyl isobutyl ketone, toluene, butyl cellosolve, 2-ethoxyethanol, methanol, ethanol, isopropanol or the like.

The substrate may be a substrate which is different in hydrophobicity or hydrophilicity from the acrylic resin of the component (A). A substrate having a hydrophobic or hydrophilic relationship with the acrylic resin of the component (A), which is suitable for coating a water-repellent component or hydrophobic in a polyimide, glass, polypropylene or polyethylene terephthalate. A polymer film material or a substrate of an inorganic material obtained by the composition.

In order to prevent foreign matter from adhering, the resin film of the present invention before use is stored in a state of being sandwiched by a protective film. The protective film can be used as a substrate.

The resin film of the present invention has characteristics suitable for use as a sacrificial layer used in the field of MEMS technology.

As described above, the resin film of the present invention does not exhibit stickiness at a normal temperature of 30 ° C or lower, and exhibits stickiness at a temperature of 50 ° C or higher. Therefore, when the resin film is placed on the portion where the sacrificial layer is formed, the bubbles can be easily removed even if bubbles are present between the two. Therefore, in the state where the air bubbles remain between the two, thermal crimping by calendering, peeling or bit of the sacrificial layer The concern of setting the offset is solved. Further, it is easy to separate the resin film before use from the protective film. Further, the temperature at which the resin film exhibits adhesion does not become extremely high, and therefore it is suitable for forming a sacrificial layer by thermocompression bonding by calendering.

The resin film of the present invention hardens at a temperature of 150 ° C or higher, and the adhesion is increased.

In the case where the sacrificial layer is formed using the resin film of the present invention, the resin film is placed on one side of the portion where the sacrificial layer is formed (that is, a component in which the sacrificial layer is sandwiched and the top and bottom positions are mutually opposed, In the case of the lower constituent elements, the other side of the portion where the sacrificial layer is formed (that is, the upper constituent element among the constituent elements in which the sacrificial layer is sandwiched between the upper and lower positions) and In a state in which the exposed surfaces of the resin film are in contact with each other, the thermocompression bonding may be performed by rolling at a predetermined temperature and for a predetermined period of time, specifically, at 150 ° C for 60 to 90 minutes. Further, when the thermocompression bonding is performed by calendering, the resin film of the present invention is heat-hardened. Hereinafter, in the present specification, the properties of the resin film of the present invention after thermocompression bonding are described as characteristics of the resin film after heat curing.

The resin film of the present invention has a small dimensional change upon thermocompression bonding by calendering. Specifically, when the thickness of the resin film is changed by thermocompression bonding in the order described in the examples described later, the thickness of the resin film measured is less than 10 μm, preferably 5 μm or less, preferably 2 μm or less. More preferably, it is 1 μm or less.

The resin film of the present invention after heat curing has sufficient adhesion strength. Specifically, the peel strength measured according to JIS C5416 is 0.2 N/cm or more is preferably 0.4 N/cm or more, preferably 1.0 N/cm or more.

The resin film of the present invention after heat curing can be dissolved and removed by selecting an appropriate organic solvent. Examples of the organic solvent to be used for this purpose include acetone, methyl ethyl ketone, methyl isobutyl ketone, DIBK (diisobutyl ketone), cyclohexanone, DAA (diacetone alcohol), and the like. Examples of the hydrocarbon solvent include toluene, xylene, solvent oil, n-hexane, isohexane, cyclohexane, and methylcyclohexane. From the viewpoint of being excellent in solubility and capable of drying at a low temperature, methyl ethyl ketone or acetone is preferred among these.

In addition, the resin film of the present invention after heat curing is excellent in workability and plating resistance when patterned by laser.

[Examples] (Example 1~39)

In the following, Examples 1 to 15 and 24 to 39 are examples, and examples 16 to 23 are comparative examples.

The components (A) to (D) are dissolved in a solvent (methyl ethyl ketone) in the blending ratio (parts by mass) disclosed in Tables 1 to 6, and the resulting solution is applied to a substrate (after release). After the treated PET film), the substrate was heated to remove the solvent, and then removed from the substrate, whereby a resin film (thickness: 30 μm) was obtained.

Further, the components (A) to (D) are as follows, respectively.

Ingredient (A)

Acrylic resin A1: methyl methacrylate butyl acrylate copolymer (ratio = 7/3, Tg: 50 ° C, Mw: 500,000, functional group: hydroxyl group, hydroxyl value: 10 [mg / KOH])

Acrylic resin A2: methyl methacrylate butyl acrylate copolymer (ratio = 7/3, Tg: 50 ° C, Mw: 510,000, functional group: hydroxyl group, hydroxyl value: 1 [mg / KOH])

Acrylic resin A3: methyl methacrylate butyl acrylate copolymer (ratio = 4/6, Tg: 20 ° C, Mw: 650,000, functional group: hydroxyl group, hydroxyl value: 10 [mg / KOH])

Acrylic resin A4: methyl methacrylate butyl acrylate copolymer (ratio = 2/8, Tg: -30 ° C, Mw: 800,000, functional group: hydroxyl group, hydroxyl value: 10 [mg / KOH])

Acrylic resin A5: methyl methacrylate butyl acrylate copolymer (ratio = 8/2, Tg: 90 ° C, Mw: 400,000, functional group: hydroxyl group, hydroxyl value: 10 [mg / KOH])

Acrylic resin A6: methyl methacrylate butyl acrylate copolymer (ratio = 7/3, Tg: 50 ° C, Mw: 550,000, hydroxyl value: 30 [mg / KOH])

Acrylic resin A7: methyl methacrylate butyl acrylate copolymer (ratio = 7/3, Tg: 50 ° C, Mw: 500,000, functional group: carboxyl group, hydroxyl equivalent: 3,900 [g/eq])

Acrylic resin a: methyl methacrylate (Tg: 120 ° C, Mw: 18,000, hydroxyl value: 150 [mg / KOH])

Ingredient (B)

Epoxy Resin B1: Bisphenol A Type Epoxy Resin (Mw: 370)

Epoxy resin B2: bisphenol F type epoxy resin (Mw: 340)

Epoxy resin B3: phenolic epoxy resin (Mw: 360)

Epoxy resin B4: biphenyl type epoxy resin (Mw: 550)

Epoxy resin B5: aliphatic epoxy resin (Mw: 290)

Ingredient (C)

Phenol resin C1: terpene phenol resin (Mw: 1100, hydroxyl value: 50 [mg/KOH])

Phenol resin C2: terpene phenol resin (Mw: 700, hydroxyl value: 35 [mg/KOH])

Phenol resin C3: bisphenol A type phenol resin (Mw: 330, hydroxyl value: 330 [mg/KOH])

Phenol resin C4: bisphenol F type phenol resin (Mw: 100, hydroxyl value: 390 [mg/KOH])

Phenol resin C5: phenolic phenol resin (Mw: 400, hydroxyl value: 370 [mg/KOH])

Ingredient (D)

Hardening Catalyst D: Tetraphenylphosphonium tetra(p-tolyl)borate

Hardening catalyst d1: imidazole

Hardening catalyst d2: tetraphenylphosphonium tetraphenylborate

Hardening catalyst d3: triphenylphosphine

The following physical properties were evaluated for the obtained resin film or the solution before the resin film was formed.

Compatibility

The solution obtained by dissolving the components (A) to (D) in a solvent (methyl ethyl ketone) was stirred until homogeneous, and the solution after standing was evaluated by the following criteria.

○: The solution after standing at room temperature for one week was in a uniform state when visually observed.

△: The solution which was allowed to stand at room temperature for 2 days was in a state of being uneven when visually observed.

×: Even if the stirring is still uneven.

Thin film

The filming was evaluated by the following criteria.

○: When a resin film was produced in the above procedure, a uniform film was obtained.

X: When a resin film was produced in the above procedure, it was not possible to form a film.

Adhesion: The adhesion of the resin film surface at 25 ° C and 60 ° C was measured using a probe adhesion tester.

Solubility: The resin film was heat-cured at 150 ° C for 60 minutes, and then dissolved in an organic solvent (methyl ethyl ketone). The evaluation is based on the following criteria.

○: completely soluble in an organic solvent.

×: swelled but not dissolved.

Then, the resin film and the copper foil (thickness: 18 μm) were thermocompression-bonded by calendering: (150 ° C, 60 minutes, 0.5 MPa) to form a laminate, and then cut into test pieces having a width of 10 mm and measured at 180°. The strength when the copper foil is torn.

Thickness change at the time of thermocompression bonding: When the resin film and the copper foil were thermocompression-bonded by rolling in the above-described order, the change in thickness of the resin film was measured.

The results are disclosed in Tables 1 to 6.

As is apparent from the table, in Examples 1 to 15, and 24 to 39 in which acrylic resins (A1, A2, A6, and A7) having a Tg of 50 ° C were used, substantially no sticking was observed at normal temperature (25 ° C). In particular, (B) is contained in an amount of 50 parts by mass or less based on 100 parts by mass of the acrylic resin of the component (A). Examples 1 to 6, 8 to 15, and 24 to 39 of the epoxy resin were particularly excellent in adhesion at room temperature (25 ° C). On the other hand, in Examples 16 to 17 in which an acrylic resin (A3, A4) having a Tg of less than 50 ° C (20 ° C, -30 ° C) was used, adhesion was exhibited at normal temperature (25 ° C). On the other hand, in Example 18 in which the acrylic resin (A5) having a Tg of 90 ° C was used, the compatibility was poor and film formation was impossible. Further, Example 19 using an acrylic resin a having a Tg of 120 ° C was inferior in compatibility. Therefore, thin film formation has not been carried out.

In the curing catalyst of the component (D), examples 1 to 15 and 24 to 39 of tetraphenylphosphonium tetra(p-tolyl)borate are used, and any of the resin films obtained by heat curing can be dissolved by an organic solvent. On the other hand, in Example 20 in which the hardening catalyst was imidazole, the resin film after heat curing was not dissolved by the organic solvent. Further, in Example 19 in which the hardening catalyst was tetraphenylphosphonium tetraphenylborate and Example 20 in which triphenylphosphine was used, the compatibility was poor. Therefore, thin film formation has not been carried out.

In any of Examples 1 to 15, and 24 to 39, the bonding strength at the time of thermocompression bonding by rolling was excellent.

Further, in the examples 1 to 15, and 24 to 39, when the thermocompression bonding was performed by rolling, the thickness variation of the resin film was small. On the other hand, in Examples 16 to 17 in which acrylic resins (A3, A4) having a Tg of less than 50 ° C (20 ° C, -30 ° C) were used, the thickness of the resin film when the thermocompression bonding was performed by rolling was large.

Further, in Example 23 of the acrylic resin containing no component (A), it was sticky at normal temperature (25 ° C), and the thickness of the resin film when thermocompression bonding by rolling was also large.

In addition, among the acrylic resins of component (A), and epoxy resin When the functional group of the reaction is a hydroxyl group, any of the carboxyl groups exhibits good physical properties (compatibility, thinning, adhesion, solubility after heat curing, adhesion strength at the time of thermocompression bonding, hot pressing) The thickness change at the time of the connection).

Further, the epoxy resin of the component (B) is either a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolac type epoxy resin, a biphenyl type epoxy resin, or an aliphatic type epoxy resin. In the case of good physical properties (compatibility, thinning, adhesion, solubility after heat curing, adhesion strength at the time of thermocompression bonding, thickness change at the time of thermocompression bonding), phenol resin of (C) component Any of terpene phenol resin, bisphenol A phenol resin, bisphenol F phenol resin, and novolac phenol resin exhibits good physical properties (compatibility, thin film, adhesion, heat hardening) Solubility, adhesion strength at the time of thermocompression bonding, and thickness change at the time of thermocompression bonding.

Claims (10)

A resin film comprising (A) an acrylic resin having a glass transition point (Tg) of 40 to 80 ° C and having a functional group reactive with an epoxy resin, (B) an epoxy resin, (C) a phenol resin, and D) tetraphenylphosphonium tetrakis(p-tolyl) borate, and the content of the epoxy resin (B) is 5 to 50 parts by mass based on 100 parts by mass of the (A) acrylic resin, and the above (C) The content of the phenol resin is 10 to 35 parts by mass based on 100 parts by mass of the above (A) acrylic resin, and the tetraphenylphosphonium tetra(p-tolyl) borate content of the above (D) component is relative to (A) 0.1 to 5 parts by mass of 100 parts by mass of the acrylic resin of the component. The resin film of claim 1, wherein the (A) acrylic resin has a hydroxyl group as a functional group reactive with the epoxy resin. The resin film of claim 2, wherein the (A) acrylic resin has a hydroxyl group value of 1 to 30 [mg/KOH]. The resin film of claim 1, wherein the (A) acrylic resin has a carboxyl group as a functional group reactive with the epoxy resin. The resin film of claim 4, wherein the (A) acrylic resin has a carboxyl equivalent of from 1,300 g/eq to 39,000 g/eq. The resin film of claim 1, wherein the mass average molecular weight (Mw) of the (A) acrylic resin is 300,000~ 800,000. The resin film of claim 1, wherein the (B) epoxy resin is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, and biphenyl type epoxy resin. And at least one of the group consisting of aliphatic epoxy resins. The resin film of claim 1, wherein the (B) epoxy resin is a bisphenol A type epoxy resin. The resin film according to claim 1, wherein the (C) phenol resin is selected from the group consisting of terpene phenol resin, bisphenol A phenol resin, bisphenol F phenol resin, and novolac phenol resin. At least one. The resin film of claim 1, wherein the (C) phenol resin is a terpene phenol resin.